Copper base alloy



Patented Jan. 2, 1940 UNITED STATES PATENT OFFICE COPPER BASE ALLOY No Drawing.

Application December 13, 1938,

Serial No. 245,409

4 Claims.

The invention relates to alloys and, more particularly, to silicon-copper alloys having improved physical and chemical characteristics.

The invention contemplates, in general, an al- 5 loy having relatively small amounts of nickel,

iron and silicon, with the remainder substantially all copper. If desired, small amounts of lead may be added to increase machinability Although the percentages may vary somewhat,

the following specific example has been found to have excellent qualities: nickel 05%, iron 1.0%, silicon 3.5% and copper 95.0%. An alloy according to the invention. is characterized by increased corrosion resistance, hardness, strength, toughness, ductility, low electrical conductivity and excellent welding qualities. may be either hot worked or cold worked and requires no special heat treatment in the manufacture or fabrication thereof.

The invention further-consists in the new and useful combinations of elements'and the new and original arrangements and combinations of steps in the process hereinafter described and more particularly set forth in the claims.

' As an illustrative embodiment of the invention, an alloy having the above composition may be prepared as follows: The copper and silicon are first charged into a crucible or furnace and melted and suitably mixed. After the above materials have been melted and mixed, the nickel is added, preferably in such amounts as will go into solution quickly and with no increase in the temperature of the bath. At the same time the nickel is added, the iron may also be added.

It is desirable that the mix be melted at a temperature of above 1150 C. Before pourmg, the melt preferably is allowed to cool to a temperature between 1120 C. minimum and 1140 C. maximum in order to obtain a sound casting without pipe and which does not spew when freezing. When pouring, it is desirable to use a pouring cup for filling the mould in order to distribute the metal evenly as it fiows into the mould and to assist in shrinking the bar, that is, teeming or filling the mould from time to time with additional metal when shrinking occurs, in order to prevent piping.

Where it is desirable that the finished alloy 50 be readily machinable. lead is added in small amounts sufficient to give a lead content in the finished alloy of approximately .10 to .50%. However, it is'desirable only to add lead where machinability is an important requirement. 'Where lead is added, it preferably is added to Such an alloy the mix only a short time before pouring, in order to prevent loss of lead by oxidation.

Thenickel content of the finished alloy may run from about 0.1 to 3.0%. The iron content of the finished alloy may run from about 0.25 to 5 5.0%. The silicon content of the finished alloy may run from 1.0 to 5.0%. The remainder will be copper, except when small amounts of lead are added, as above indicated. Although the various constituents all contribute to provide the 0 excellent characteristics of the alloy, it is believed that the presence of the nickel makes the alloy workable, tough and ductile and improves its elasticity. The iron imparts hardness to the alloy without requiring special heat treat- 15 ment other than the ordinary process anneals. The silicon makes the alloy more corrosion resistant, improving its hardness, reducing its electrical conductivity and increasing its tensile strength.

Although an alloy having a composition falling anywhere within the above ranges has the excellent characteristics herein pointed out, the alloy containing approximately 0.5% nickel, 1.0% iron, 3.5% silicon and 95.0% copper is given as a 25 particular illustrative embodiment.

An alloy of the above composition, when soft drawn or soft rolled, has been found to have a tensile strength of approximately 70,000 PSI,

a yield point of 30,000 PSI, an elongation of 47% 30 in two inches, and a hardness on the Rockwell B scale with a ball of -70. When hard rolled, the alloy has been found to have a tensile strength of 118,000 PSI, a yield point of 65,000 PSI, an elongation of 2% in two inches, and a 36 hardness on the Rockwell B scale with a 1 5'" ball of 100. The modulus of elasticity is 165x10 The electrical conductivity is approximately 7%.

No particular heat treatment'is necessary in 40 the fabrication of the material other than the ordinary process anneals. The alloy can be. hot rolled or forged at a temperature of at least F. higher than that of many other copper-silicon alloys. For example, this alloy can be rolled at 45 a temperature of around 1600 F. which permits greater reductions between'heats than heretofore possible.

At the critical temperature of annealing,

namely, 1500 F., without quenching, the ma- 60- terial is sufiiciently softened to permit stretching or patent leveling and flattening when cold. This alloy will permit a greater amount of cold work than many of the usual copper-silicon alloys.

The alloy is inherently resistant to corrosion and Us by reason of the great hardness obtained without special heat treatment, it has a very high resistance to abrasion.

Some of the commercial uses for this alloy are: tanks or boilers for water or chemicals; paper print rollers on which designs are etched; paper mill equipment, such as paper pulp chests, screen, plates, Jordan or beater bars; leaf springs for electrical contacts and for mechanical uses; thrust bearings for taking shocks; sanitation equipment; textile equipment; turbine blading;

pump liners and rods, etc. The alloy can be readily welded electrically and the weld or seam has exceptionally high strength and resistance range of from about 30,000 to 65,000 PSI, a modulus of elasticity of about 16.6 10, and an elongation range of from about 2 to 47% in two inches.

2. A copper base alloy composed of from about 1.0 to 5.0% silicon, from about 0.25 to 5.0% iron, from about 0.1 to 3.0% nickel, the remainder all copper, said alloy being characterized by high ductility, elasticity, tensile strength and hardness, by high resistance to corrosion and abrasion, and by excellent welding properties.

3. A copper base alloy composed of approxi mately 1.0 to 5.0% silicon, approximately 1.0% iron and approximately 0.5% nickel with the remainder all copper, characterized by high tensile strength, hardness, elasticity, toughness, resistance to abrasion and having excellent welding properties.

4. A copper base alloy composed of approxi-. Y mately 1.0 to 5.0% silicon, approximately 1.0%

iron and from 0.1 to 3.0% nickel with the remainder all copper, said alloy being characterized by high ductility, elasticity, tensile strength and hardness, by high resistance to corrosion and abrasion, and by excellent welding properties.

' ELMORE S. STRANG.

RICHARD O. FARMER, 

